Parrotfish make themselves a kind of mucus 'sleeping bag' which masks their smell from predators and keeps parasites away.
4
Cows can sleep standing up, but they can only dream lying down.
745
A cat rubs against people not only to be affectionate but also to mark out its territory with scent glands around its face. The tail area and paws also carry the cat's scent.
293
Dire wolves actually existed, living up to 10,000 years ago before going extinct.
10
Dolphins have names for one another.
18